1. Field
The presently disclosed subject matter relates to headlight controllers and vehicle headlight systems, and more particularly to vehicle headlight systems including an adaptive driving beam (ADB) using an optical unit, and the vehicle headlight systems having favorable light distribution patterns, which can be easy to drive at night, and which can prevent the optical unit from emitting a glare type light to oncoming vehicles on an oncoming traffic lane and vehicles moving forward on a driving lane.
2. Description of the Related Art
When drivers steer a car at night, the drivers usually want to steer the car while they turn on headlights for a high beam to improve a visibility. However, drivers must drive the car while they switch between the headlights for a high beam and headlights for a low beam in response to various traffic conditions so that the headlights do not emit a glare type light to oncoming vehicles, vehicles moving forward on a same driving lane, etc. Hence, the drivers always tend to employ the headlights for a low beam in a downtown due to their burdens of the switching operation, and also tend to employ the headlights for a high beam in a suburb.
In these cases, the drivers may frequently give a glare type light to oncoming vehicles, vehicles moving forward on a same driving lane and the like in some cases of traffic conditions such as a hill, a rough road, etc. Accordingly, vehicle headlight systems including an adaptive driving beam (ADB) have been developed. A vehicle headlight system including an ADB, for example, may contribute an improvement of visibility in a forward direction of a subject vehicle that has the ADB for drivers by detecting an oncoming vehicle, a forward vehicle and the like with a camera incorporated into the subject vehicle that has the ADB and by emitting a high beam for the drivers on an area except regions where the oncoming vehicle and the forward vehicle exist.
Therefore, the vehicle headlight system including an ADB may avoid the glare type light to oncoming vehicles, vehicles moving forward on a same driving lane and the like, and also may improve a visibility in a forward direction of the subject vehicle that has the ADB for the drivers while promptly detecting pedestrians for safe driving. A conventional headlight system including such an operation of ADB is disclosed in Patent Document No. 1 (Japanese Patent Application Laid Open JP 2015-16774). FIG. 7a is a schematic explanatory diagram depicting a conventional headlight system including an ADB, and FIG. 7b is a schematic explanatory view depicting a light distribution pattern of the conventional headlight system shown in FIG. 6a, which is disclosed in Patent Document No. 1.
The conventional headlight system 50 includes: a left lamp unit 51L including a left low beam lamp 51LL, a left high beam lamp 51LH, a left ADB lamp 51LA and a first lamp controller 52L configured to control the left low beam lamp 51LL, the left high beam lamp 51LH and the left ADB lamp 51LA; a right lamp unit 51R including a right low beam lamp 51RL, a right high beam lamp 51RH, a right ADB lamp 51RA and a second lamp controller 52R configured to control the right low beam lamp 51RL and the right high beam lamp 51RH in accordance with a high-low signal output from the first lamp controller 52L via a lamp network 56, and the right ADB lamp 51RA being connected to a line 57 so as to be controlled by the first lamp controller 52L of the left lamp unit 51L; a headlight controller 53 connecting to the first lamp controller 52L and the second lamp controller 52H via a controller network 54, and configured to control the first lamp controller 52L and the second lamp controller 52R; and a camera 55 connecting the controller network 54 to output image data detected by the camera 55 to the leadlight controller 53, as shown in FIG. 7a. 
The conventional headlight system 50 may form a light-emitting region where includes a first projecting region An, a second projecting region An+1, a third projecting region An+2 and a fourth projecting region An+3 each having a light-emitting intensity (cd) as shown in FIG. 7b. When subject vehicles using the conventional headlight system 50 move from a rearward direction of vehicles moving forward on a same driving lane, 1,740 cd (Bf) is a light-emitting intensity, which may avoid the glare type light to the vehicles moving forward. When vehicles using the conventional headlight system 50 pass by oncoming vehicles on an oncoming traffic lane approaching in a direction toward the subject vehicles on a driving lane, 625 cd (Bo) is a light-emitting intensity, which may avoid the glare type light to the oncoming vehicles.
Hence, when the subject vehicles using the conventional headlight system 50 move from the rearward direction of the vehicles moving forward on the same driving lane, the subject vehicles may not emit the glare type light to the vehicles moving forward by controlling the headlight light system 50 using a light distribution pattern PADBf for the vehicles moving forward on a driving lane. Similarly, when the subject vehicles using the conventional headlight system 50 pass by the oncoming vehicles on the oncoming traffic lane approaching in the direction toward the subject vehicles on the driving lane, the subject vehicles may not emit the glare type light to the oncoming vehicles by controlling the headlight light system 50 using a light distribution pattern for the oncoming vehicles.
Specifically, the subject vehicles using the conventional headlight system 50 may drive using the light distribution pattern PADBf for the vehicles moving forward or the light distribution pattern PADBo for the oncoming vehicles. When the subject vehicles using the conventional headlight system 50 detect an oncoming vehicle with the camera 55, the subject vehicles may turn off the second projecting region An+1 and the third projecting region An+2 and may employ a light distribution pattern PADBo1 for the oncoming vehicle so as not to emit the glare type light to the oncoming vehicle by controlling the headlight light system 50. After the subject vehicles using the conventional headlight system 50 passed by the oncoming vehicle on the oncoming traffic lane, the subject vehicles may return to the light distribution pattern PADBo from the light distribution pattern PADBo1.
Similarly, when the subject vehicles using the conventional headlight system 50 detect a vehicle moving forward on the same driving lane with the camera 55, the vehicles may turn off the second projecting region An+1 and the third projecting region An+2 in the light distribution pattern PADBf for the vehicle moving forward so as not to emit the glare type light to the vehicles by controlling the headlight light system 50. After the vehicles using the conventional headlight system 50 have not detected the vehicle moving forward on the driving lane, the vehicles may return to the light distribution pattern PADBf.
However, in the subject vehicles using the conventional headlight system 50 which repeats such a lighting control, for example, when the conventional headlight system 50 turns off the second projecting region An+1 and the third projecting region An+2 in the light distribution pattern PADBo for the oncoming vehicles from the light distribution pattern PADBo emitting all projecting regions, each of light-emitting intensities of overlapping regions between the first projecting region An and the second projecting region An+1 and between the third projecting region An+2 and the fourth projecting region An+3 may reduce because the conventional headlight system 50 turns off the second projecting region An+1 and the third projecting region An+2, as shown by dotted lines in the light distribution pattern PADBo1.
Accordingly, such the lighting control may cause a degradation of visibility in a forward direction of the subject vehicles using the conventional headlight system 50. Especially, each of light-emitting intensities of the above-described overlapping regions must be lower than each of middle portions of the first projecting region An and the fourth projecting region An+3, respectively. Furthermore, because each of light-emitting intensities of the overlapping regions corresponds to a respective one of edge portions of light-emitting portions, the respective one of edge portions of the light-emitting portions should be bright for drivers of the subject vehicles using the conventional headlight system 50.
The above-referenced Patent Documents and additional Patent Documents are listed below and are hereby incorporated with their English abstracts and specification in their entireties.    1. Patent Document No. 1: Japanese Patent Application Laid Open JP 2015-16774    2. Patent Document No. 2: Japanese Patent No. 5,692,520    3. Patent Document No. 3: U.S. Pat. No. 8,373,182    4. Patent Document No. 3: U.S. Patent Publication No. US-2015-0055357-A1
The disclosed subject matter has been devised to consider the above and other problems, characteristics and features. Thus, exemplary embodiments of the disclosed subject matter can include headlight controllers including an adaptive driving system (ADB) for controlling a right and left headlight be capable of projecting a plurality of light-emitting patterns in a plurality of light-emitting areas, wherein the plurality of light-emitting patterns align in a horizontal direction of a road, each of the light-emitting patterns is independently drown, each of the adjacent light-emitting patterns overlaps with respect to each other without a space between the adjacent light-emitting patterns, and each of edge portions of the plurality of light-emitting areas is a respective one of non-overlapping regions of the adjacent light-emitting patterns and each of middle portions of the plurality of light-emitting areas is a respective one of overlapping regions of the adjacent light-emitting patterns.
The headlight controller can provide favorable light distribution patterns to safely drive at night in accordance with various traffic conditions, while preventing a right and left headlight from emitting a glare type light to oncoming vehicles and vehicles moving in a forward direction of a subject vehicle incorporating the headlight controller and the right and left headlight. Additionally, exemplary embodiments of the disclosed subject matter can include vehicle headlight systems including a right and left optical unit with a simple structure, which can be used as the right and left headlight for the above-described headlight controller. The optical unit does not include a plurality of lamps such as the conventional headlight system, and therefore can expand possibilities for design so as to be able to harmonize with various vehicular designs.